Bruce just use a feeler gauge and squeeze what you need. Of thefew cranks I have done <japanese two strokes> they really dont have that much of a tight fit where the press jumps. every one I assembled squeezed in smoothly so you just give a squeeze measure with a feeler gauge give a squeeze etc etc.
It appears to be a straightforward tool use the correct bushings,line all parts up and squeeze in a shop press. Might take you 10/15 minutes to set up but it has to be better than the possible hours spent knocking your crank around with a brass hammer.
Dave, if you think about it the price of the jig is not too much if have to buy a brass hammer, 3 dial indicators and a truing stand if you are dedicated to rebuilding cranks but the dial indicators and brass hammer can see a lot of different uses compared to the jig.